Life-cycle inventory, components

LCA activity has three components as defined by the Society of Environmental Toxicology and Chemistry (SETAC) life-cycle inventory, life-cycle impact assessment. 

There have been a number of studies on fuels used for electricity generation. One of these studies focuses on the use of natural gas, heavy oil, or coal in cogeneration of electricity.112 Using a numerical eco-load total standardized evaluation system, these authors found that coal had the lowest eco-load of all alternatives considered. In another LCA study, Goralczyk113 compares hydroelectric, photovoltaic cells, wind turbines, oil, coal, and natural gas and quantifies that electricity from hydropower had the least environmental impact. Schleisner114 focuses on wind farms in a life-cycle inventory study that focuses on the materials used to manufacture the windmills and reports that 2% of the electricity generated during the windmill s lifetime is used to manufacture the windmill components. 

In this case, the component approach based on life cycle inventory was employed (Monfreda et al., 2(X)4). Thus, individual EFs were calculated for each material and... 

The components of a life cycle analysis include the life cycle inventory. These involve a complete resource requirement to be identified in terms of materials and eneigy. The life cycle impact assessment characterizes and assesses the effects of the environmental emissions. The life cycle Improvement analysis is used to quantify the life cycle inventory and import, and is used to assess possible environmental improvements that can be made. 

Life-cycle impact assessment Technical, quantitative, and/or quaUtative process to characterize and assess die effect of die environmental loading identified in die inventory component. 

It is environmentally important to perform a life cycle assessment analysis, not only for non-biodegradable polymers but also for partially biodegradable or even completely biodegradable polymers. Life cycle analysis (LCA) is a tool which helps in understanding the environmental impact associated with the products, processes and activities throughout the life of a polymer. The life cycle of vegetable oil-based polymers is shown in Rg. 2.6. Thus a complete LCA would include three separate but interrelated components, an inventory analysis, an impact analysis and an improvement analysis. 

Life cycle assessment involves an inventory analysis to provide information about the consumption of material and release of wastes from the point that raw material is obtained to make a product to the time of its ultimate fate, an impact analysis to consider the environmental and other impacts of the product, and an improvement analysis to determine the measures that can be taken to reduce impacts. A life cycle assessment gives a high priority to the choice of materials in a way that minimizes wastes. It considers which materials and whole components can be used or recycled. And it considers alternate pathways for manufacturing processes or, in the case of chemical manufacture, alternate synthesis routes. 

As the specially designed common components in the core product, which can be standardized, may increase the cost of materials, companies must carefully assess whether the benefits of standardization outweigh the added costs. Using standardized components decreases the size of the needed buffer inventory. As buffer inventory increases in the uncertainty, standardized components in the core helps reduce cost in a volatile market. For example, products with shorter life cycles increase uncertainty, increasing the benefits of standardization. 

Let us pause and take an inventory of the situation up to this point. (1) We have a plausible mechanism of modulation of both components of WF of a selective layer (palladium) and (2) we have at least two methods of measurement of this effect, the macroscopic Kelvin probe and a field-effect transistor. However, the placement of the selective layer within the structure used for either measurement determines whether the effect is observable. In order to explain this caveat, we add another layer of the same metal M between Pd and the insulator in the structure shown in Fig. 6.33. This would correspond to the real life situation when we would try to connect a selective layer by a wire to the IGFET or a Kelvin Probe. It is not necessary to perform the same cycle as we did in Fig. 6.33. Instead, we add the individual energy contributions in the cycle, which begins and ends at the silicon Fermi level (moving again anticlockwise) ... 

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